Police were called to the property at around 3.30am on Saturday following a request for assistance by the ambulance service.

His father, named locally as Kye Gbangbola and aged in his 40s, and his mother, in her 30s, remain in hospital in serious conditions. They are not thought to be life threatening.

Zane Gbangbola was described as "such a lovely little boy"

Fifteen people, including two Surrey Police officers, were also taken to hospital as a precaution.

The boy's taekwondo instructor, Anoop Hothi, posted a message on Facebook: "My neighbours' little boy passed away ... He was such a lovely little boy, lovely parents. It was a joy to teach you martial arts little man."

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Police refused to comment on speculation the death was related to carbon monoxide poisoning, but advised anyone in the Thameside area in Chertsey who showed signs of vomiting, diarrhoea and fever to seek medical assistance.

But a statement from the Environment Agency on Sunday said analysis of water samples at the house had not revealed anything that could have led to Zane's death.

It said: "Yesterday evening water samples were obtained from the basement of the property by Environment Agency staff and analysed overnight with support from Thames Water.

"Based on the results of the analysis, we have concluded that there is nothing in the water samples that may explain the cause of the incident. The Environment Agency is continuing to assist on the ongoing police enquiry."

Access to the family's home was hindered by floodwaters covering nearby roads. Friends have described the seven-year-old as a "lovely little boy" who was looking forward to getting a new puppy.

A specialist team from the fire service was deployed to the scene to investigate the circumstances.

Nearby homes were evacuated as a precaution and people were advised to go to hospital to be checked.

Chief Superintendent Dave Miller told a news conference: "It is very sad that a young child has died earlier today - our thoughts are with his parents who are currently ill in hospital.

"Police officers are currently with them and we will continue to offer our support during this difficult time.

"The cause of the illness is currently unknown but what I can confirm is that the people who were taken ill are from a very localised area.

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"We cannot rule out that there may be a link to flooding in the local area and whilst the investigation is ongoing local residents should follow sensible precautions."

Sky's Siobhan Robbins said: "Many of those properties have been flooded over the last few weeks, they have been pumping out and because of that the local community have been gathering at the Kingfisher pub just across the bridge.

"They saw the family last night, they were chatting and they were in good spirits.

"Many local people are extremely shocked and saddened to hear of the death of a seven-year-old boy."

IT worker David North, who works in Chertsey, said he saw a yellow hose hanging from a ground floor window of the property at the centre of the alert.

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Sunday, February 9

He said: "I saw a yellow hose coming from the front window on the ground floor. Whether it was pumping out water or something else, I don't know.

"My understanding is that this incident was found out while evacuations were being carried out due to the flooding."